What is the LAY file format?
A .lay file contains metadata for a DVD video project created with Apple DVD Studio Pro. .lay is a proprietary format owned by Apple and is not supported by any other software application. Data in a .lay file are necessary for the given project to function properly, but serve only a supportive, build-time role and as such are not transferred to the disc. However, if a .lay file is present on a burned disc, it means that a mistake has been made during the disc writing process - such a file is effectively useless on the finished medium.
A .lay file is typically saved in the VIDEO_TS folder and is named VOB_DATA.LAY by default. There is no publicly documented file signature; it is an internal working artifact produced during authoring, not intended to be opened directly.
.lay is the native layout file for DVD Studio Pro, a software tool for authoring videos developed by Apple. The tool is based on Astarte's DVDirector software source code acquired by Apple in 2000, and was first introduced as DVD Studio Pro 1.0 in 2001. The application was tightly integrated with other video editing tools offered by Apple, namely Final Cut Pro and Motion. DVD Studio Pro was last updated as version 4 in 2005 and ceased to be supported in 2011, with many of its features implemented in Final Cut Pro Studio. The .lay file coexists with .VOB, .IFO, and .BUP files in the VIDEO_TS structure, which is typically packaged as an .ISO disc image.
Security & safety
RISK: LOWA DVD Studio Pro .lay is internal project metadata, not an executable, so it poses no direct risk. The practical caution is identity: confirm the file actually came from a DVD Studio Pro project before assuming this meaning, since .lay is shared by many unrelated formats. Don't install dubious 'LAY file openers' found via search.
Format details
in a nutshell- Keyboard layout file - Some keyboard-mapping tools and OSes store key layouts as .lay (e.g. legacy keyboard utilities).
- FaxWorks / spreadsheet & CAD layout files - FaxWorks fax layouts, Quattro Pro/older spreadsheet layouts, and various CAD/PCB tools have used .lay for page or board layout data.
Programs that open LAY files
macOS1 app
Apple DVD Studio Pro (legacy)
Paid The file belongs to a DVD Studio Pro project; open the PROJECT in DVD Studio Pro, not the .lay alone. The app is discontinued (2011) and runs only on older macOS. Technical details
deep spec| Developer | Apple, Inc. |
| Platform | Mac OS X (macOS) only |
| Purpose | Stores disc layout and sector-placement metadata generated during DVD authoring and burning |
| Default filename | VOB_DATA.LAY |
| Default location | VIDEO_TS folder inside the DVD Studio Pro project |
| File encoding | Binary (application-internal; structure undocumented) |
| File signature (magic bytes) | None publicly documented |
| Typical file size | A few KB to low MB (layout metadata only; no media content) |
| Format version | Tied to DVD Studio Pro version (1.x-4); internal versioning undocumented |
| MIME type | application/octet-stream |
| Associated project format | .dvdproj (DVD Studio Pro project bundle) |
| Related VIDEO_TS files | .VOB (video object), .IFO (disc info), .BUP (IFO backup) |
| Disc persistence | Not included in the final burned disc; presence on a disc indicates a burning error |
| Released | 2001 (Apple DVD Studio Pro 1.0) |
| Latest version | DVD Studio Pro 4 (2005; final release, discontinued 2011) |
| Specification | en.wikipedia.org |
LAY conversions
Community Q&A
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